Hi All, Opening a new file is done in 2 steps on regular filesystems: 1. Call the create inode-op on the parent-dir to create an inode to hold the meta-data related to the file. 2. Call the open file-op to get a handle for the file. vboxsf however does not really use disk-backed inodes because it is based on passing through file-related system-calls through to the hypervisor. So both steps translate to an open(2) call being passed through to the hypervisor. With the handle returned by the first call immediately being closed again. Making 2 open calls for a single open(..., O_CREATE, ...) calls has 2 problems: a) It is not really efficient. b) It actually breaks some apps. An example of b) is doing a git clone inside a vboxsf mount. When git clone tries to create a tempfile to store the pak files which is downloading the following happens: 1. vboxsf_dir_mkfile() gets called with a mode of 0444 and succeeds. 2. vboxsf_file_open() gets called with file->f_flags containing O_RDWR. When the host is a Linux machine this fails because doing a open(..., O_RDWR) on a file which exists and has mode 0444 results in an -EPERM error. This series fixes this by adding support for the atomic_open directory-inode op. Hans de Goede (4): vboxsf: Honor excl flag to the dir-inode create op vboxsf: Make vboxsf_dir_create() return the handle for the created file vboxsf: Add vboxsf_[create|release]_sf_handle() helpers vboxsf: Add support for the atomic_open directory-inode op fs/vboxsf/dir.c | 76 +++++++++++++++++++++++++++++++++++++++------- fs/vboxsf/file.c | 71 +++++++++++++++++++++++++++---------------- fs/vboxsf/vfsmod.h | 7 +++++ 3 files changed, 116 insertions(+), 38 deletions(-) Regards, Hans
